Chapter 10

Air Quality

Learning Objectives

By the end of this chapter the reader will be able to:• Describe historically important air pollution episodes• List health effects associated with air pollution• Describe potential hazards linked to indoor air• Enumerate the typical components of urban ambient

air pollution• Discuss the concept of global warming

Air Quality

• Many European cities do not meet World Health Organization (WHO) air quality standards for at least one pollutant.

• In the U.S., about a quarter of the population lives in areas that do not meet U.S. air quality standards.

Smog

• Smog denotes “A mixture of pollutants, principally ground-level ozone, produced by chemical reactions in the air involving smog-forming chemicals.”

• Formed by anthropogenic and/or natural sources

Health Effects of Air Pollution

• Some forms of cancer such as lung cancer and skin cancer (from possible depletion of the ozone layer)

• Damage to vital tissues and organs, such as the nervous system

• Impairment of lung and breathing function

Environmental Impacts of Air Pollution

• Causes property damage • Reduces visibility in national parks • Harms forests• Harms lakes and other bodies of water• Injures wildlife

Lethal Air Pollution Episodes in History

• Meuse Valley in Belgium (1930)

• Donora, Pennsylvania (1948)

• London, England (1952)

Composition of Pure Air (by Weight)

• Nitrogen (76%)

• Oxygen (23%)

• Argon (1%)

• Carbon dioxide (0.03%)

• Variety of other gases in lesser amounts

• Water vapor

Natural Sources of Air Pollution

• Wind storms that spread dust clouds

• Salt evaporation along the earth’s coasts

• Production of materials that have a biologic origin (e.g., mold spores, pollen, and organic material from plants and animals )

• Forest fires

• Volcanic eruptions

Figure 10-5 Eruption of Mount Saint Helens on May 18, 1980.

Source: Reprinted from the Centers for Disease Control and Prevention. Public Health Image Library. ID #4726. Available at: http://phil.cdc.gov/Phil/details.asp. Accessed March 22, 2010.

Anthropogenic Sources of Air Pollution

• Stationary sources

• Mobile sources

Stationary Sources

• Electric generating plants

• Factories and manufacturing complexes

• Oil refineries

• Chemical plants

• Incinerators

Mobile Sources

• On-road vehicles (e.g., cars, trucks, buses)

• Off-road vehicles (e.g., dune buggies, snowmobiles)

• Nonroad vehicles (e.g., airplanes, ships, trains)

Mobile Sources and Air Pollution

• According to the EPA, motor vehicles produce nearly half of two major causes of smog—volatile organic compounds (VOCs) and nitrogen oxides (NOx)—almost 75% of carbon monoxide, and more than half of emissions of toxic air pollutants.

Common Componentsof Air Pollution

• Sulfur oxides• Particulate matter• Oxidants (including ozone)• Carbon monoxide• Hydrocarbons• Nitrogen oxides• Lead• Other heavy metals

Criteria Air Pollutants

• Used to describe “A group of very common air pollutants regulated by EPA on the basis of criteria (information on health and/or environmental effects of pollution).”

• Criteria air pollutants are ozone, nitrogen oxides, carbon monoxide, sulfur dioxide, particulate matter, and lead.

Particulate Matter (PM)

• PM10 and PM2.5

• Particles of both sizes cause respiratory system irritation and impact the lungs.

• PM2.5 particles are capable of being inhaled deeply into the lungs.

• PM2.5 particles are not cleared readily from the body.

• PM2.5 particles are associated with 60,000 deaths annually (U.S.).

Acid Rain

• Refers to the precipitation of acidic compounds formed when components of air pollution (e.g., SO2 and NOx) interact with other components in the air such as water, oxygen, and oxidants.

• Emissions of SO2 and NOx are produced by installations such as electric utility plants.

• Creates abnormally high levels of acidity that are potentially damaging to the environment, wildlife, and human health.

Source: Reprinted from US Environmental Protection Agency. AIRTrends 1995 Summary: Acid Rain. Available at: http://www.epa.gov/air/airtrends/aqtrnd95/acidrain.html. Accessed March 22, 2010.

Figure 10-9 Acid rain formation.

Temperature Inversion

• An atmospheric condition during which a warm layer of air stalls above a layer of cool air that is closer to the surface of the earth

• During a temperature inversion, pollutants can build up when they are trapped close to the earth’s surface.

Diesel Exhaust

• A complex mixture of particles and gases; includes the element carbon, condensed hydrocarbon gases, and polycyclic aromatic hydrocarbons (PAHs), the latter suspected of being carcinogens.

• Other constituents are hundreds of organic and inorganic compounds, some of which are regarded as toxic air pollutants.

Health Effects of Diesel Exhaust

• Epidemiologic evidence suggests that in comparison with nonexposed groups, two categories of workers (truck drivers and railroad crews) exposed directly to diesel exhaust have lung cancer incidence rates that are 20% to 40% higher.

The Air Quality Index

• The Air Quality Index is used to provide the public with an indication of air quality in a local area on a daily basis.

• It focuses on health effects you may experience within a few hours or days after breathing polluted air.

National Ambient Air Quality Standards (NAAQS)

• Federal standards for air pollution

• The EPA reviews the scientific literature at 5-year intervals and decides whether to revise each standard.

Federal Standards

• “Primary standards set limits to protect public health, including the health of ‘sensitive’ populations such as asthmatics, children, and the elderly.”

• “Secondary standards set limits to protect public welfare, including protection against decreased visibility, damage to animals, crops, vegetation, and buildings.”

Acute Effects of Air Pollution

• Irritation of the eyes, nose, and throat• Aching lungs• Bronchitis• Pneumonia • Wheezing• Coughing• Nausea• Headaches

Chronic Effects of Air Pollution

• Heart disease

• Chronic obstructive pulmonary disease

• Lung cancer

Poor Indoor Air Quality(Many People Spend 90% of Time Indoors)

• Related to exacerbation of asthma and bronchitis

• Associated with:– Legionnaires’ disease– Sick building syndrome– Hypersensitivity pneumonitis– Multiple chemical sensitivity

Indoor Air Pollution Sources

• Mold and bacteria

• Carbon monoxide fumes from attached garage

• Chemicals released from building and furnishing materials

• Tobacco smoke

• Gases including radon seeping through foundation

Indoor Cooking Stoves in the Third World

• Use biomass fuels

• Often unventilated

• Impact the health of children, women, and the elderly disproportionately

Illness Associated with Poor Indoor Air Quality

• Sick building syndrome– No specific illness or cause can be identified.– Causes acute health and comfort effects

• Building-related illness– Describes a diagnosable illness– Linked to specific pollutants

Global Warming

• “An increase in the near surface temperature of the Earth. . . . [is] predicted to occur as a result of increased emissions of greenhouse gases.”

• “Scientists generally agree that the Earth’s surface has warmed by about 1 degree Fahrenheit in the past 140 years.”

Causes of Global Warming

• Use of fossil fuels, including coal and petroleum-based fuels

• Chlorofluorocarbon gases used in air conditioners have been linked to the depletion of the ozone layer.

Source: Reprinted from US Environmental Protection Agency. AIRTrends 1995 Summary, Global Warming and Climate Change. Available at: http://www.epa.gov/air/airtrends/aqtrnd95/globwarm.html. Accessed March 22, 2010.

Figure 10-19 The greenhouse effect.

Potential Impacts of Global Warming

• Disturbances in the native habitats of plant and animal species

• Growth of vector-borne diseases

• Growth of organisms in the ocean that cause foodborne seafood poisoning

More Potential Impacts of Global Warming

• Exacerbation of the effects of air pollution

• Extreme climatic conditions (e.g., heat waves, droughts, and monsoons)

• Disruption of the food supply and dwindling of food resources

Air Pollution in the U.S.

• U.S. produces 23% of the earth’s emissions of greenhouse gases.

• Major source of air pollution in the U.S. is combustion of fossil fuels, particularly by coal-fired electric generating plants and internal combustion engines.

• The U.S., with only about 4% of the world’s population, is the leading source of carbon dioxide pollution.

Steps to Reduce Emissions of Harmful Air Pollution

•Technological controls

•The Kyoto Protocol

•Energy conservation

Technological Controls

• Several mechanical devices are used to reduce industrial emissions of particulate matter (e.g., scrubbers, filters, and electrostatic precipitators).

What is the Kyoto Protocol?

• An international and legally binding compact that was initiated in Kyoto, Japan, in 1997.

• Goal is to reduce emissions of greenhouse gases that are believed to be the cause of recent climate changes.

• Requires developed countries to reduce their emissions by targeted amounts. For example, the U.S. would be required to cut emissions by 7% and European countries (Switzerland, Central and Eastern Europe, and the European Union) by 8%.

More about the Kyoto Protocol

• In order for the Kyoto Protocol to come into effect, it needed to be ratified by a sufficient number of industrialized countries that in combination produce at least 55% of the world’s total CO2 emissions.

• By February 2005, 141 nations including Russia had ratified the protocol, meaning that it could be implemented. The Kyoto Protocol went into force on February 16, 2005. The U.S. did not ratify.

Copenhagen Accord, 2009

• Spearheaded by the U.S., China, and several other countries

• Sought to curb greenhouse gases and keep global temperature increase below 2 degrees Celsius between 2010 and 2040

• Talks became deadlocked

Energy Conservation Steps to Reduce Air Pollution

• Increase the efficiency of older power plants.• Develop more renewable and alternative energy

sources, e.g., wind turbines and solar panels.• Use energy-efficient designs in home construction and

electrical appliances; try to reduce dependence on such appliances.

• Increase the fuel efficiency of motor vehicles as in the use of hybrid gas-electric and other high- mileage designs.

• Increase the use of public transportation.